The Inmarsat Fleet F55 antenna and below deck unit are smaller than the Inmarsat Fleet F77 equivalents and particularly suitable for installation onboard a wide range of vessels, including medium-sized merchant ships, large yachts, fishing vessels, patrol boats and offshore support craft.

The Fleet F55 terminal provides global voice services, as well as 64kbits/s Mobile ISDN (including G-3 fax at 14.4kbps, or full-blown G-4 fax) and Mobile Packet Data. It supports a comprehensive selection of interfaces, including ISDN, X.21, RS449, RS232, and two RJ11 ports, as well as optional STUIIB/III service for reliable secure communications.